1. Field of the Invention
The present invention relates in general to battery testing devices and in particular to a simple and inexpensive battery tester which will accommodate any size of 1.5 volt and 9 volt batteries.
2. Description of the Prior Art
Dry cell batteries are manufactured in many different standard sizes. Typically, 1.5 volt batteries are cylindrical in shape and have a positive terminal or pole and a negative terminal or pole located at opposite ends of the cylinder. On the other hand, 9 volt batteries are generally shaped in the form of a rectangular parallelepiped, with both the positive and negative poles located on the same face. Batteries such as these are commonly stored in wholesale and retail outlets for a number of months prior to sale. Improper storage during this time or storage for long periods can cause the batteries to lose their stored electrical energy. Also, faulty construction can cause power loss in the batteries prior to use and discharge through normal use will render batteries weak or nonusable. It has therefore been desirable to provide a simple and inexpensive battery tester for use in a retail store or a home which will accommodate any size of commercial dry cell battery and which can be quickly and simply used, even by a child, to indicate the condition of a battery or set of batteries.
My U.S. Pat. No. 3,736,498 discloses a battery tester for a 1.5 volt cylindrical battery. The battery tester includes an indicator lamp carried by an arm extending over a base which receives a battery to be tested. The arm is attached to a plunger, vertically slidable within a stem connected to the base. Conductive means on the base, stem, plunger, and arm provide a partial circuit between the lamp and a lower negative pole of the battery in contact with the base. Depression of the arm from its uppermost position places a rotating terminal on the lamp in contact with an upper positive pole on the battery, thereby completing the circuit between the battery and the lamp. This device is simple and easy to operate but will work only batteries of one voltage and with the terminals or poles at opposed ends of the cylindrical body, as is the case with 1.5 volt flashlight type batteries. Other battery testers are shown in U.S. Pat. Nos. 2,155,778, 2,205,316, 2,833,984 and 3,395,809, but each of these will accommodate only a battery of a single voltage having oppositely-facing terminals like the common 1.5 volt flashlight battery.